domain.TLD       where TLD (Top Level Domain) is com, net, org etc
domain.ccTLD     where ccTLD (Country Code TLD) is say .de
domain.SLD.ccTLD where SLD.ccTLD (Second Level Domain ccTLD) is com.au, co.uk, etc

# additionally we may have as a prefix
www.domain....
subdomain.domain.....
subsubdomain.subdomain.domain.....